Biochemistry Quiz on Uric Acid and Phenylketonuria

Waste Classification

• Green: Non-Infectious Wet Waste
• Black: Infectious Dry Waste
• Orange: Radioactive Waste

Biosafety Overview

• Designed to protect workers, communities, and the environment from exposure or release of infectious agents and toxins.
• Utilizes specific practices, training, safety equipment, and specially designed buildings.

Disinfection Guidelines

• Recommended disinfectant: Household bleach.
• Preparation: Mix 10 mL of bleach with 90 mL of water for a concentration of 55 ppm for sanitation; use 600-800 ppm for disinfection.
• Solution is to be made fresh daily and properly labeled with name, preparation date, expiration (24 hours), and preparer’s initials.

Biohazard Exposure Routes

• Airborne: Exposure occurs from splashes and aerosols, particularly with airborne diseases.
• Safety Practices: Use of PPE, including masks, along with safety shields and guards is crucial.

Types of Casts in Urine Analysis

• Bacterial Casts: Indicative of contamination; may result from older specimens.
• Granular Casts: Finely granular, indicating degeneration, linked to glomerulonephritis and nephrotic syndrome.
• Fatty Casts: Associated with diabetes mellitus; represent the final form of various casts.
• Waxy Casts: Glass-like appearance, associated with chronic renal failure.
• Broad Casts: Indicative of renal failure; show widening of tubular walls.

Urinary Crystals

• Crystaluria: Excretion of urine crystals, formed by the precipitation of solutes; significant factors include pH and temperature.
• Calcium Carbonate Crystals: Form effervescence upon adding acetic acid.

Metabolic Disorders Related to Urine

• Phenylketonuria: A well-known aminoaciduria linked to a defective gene causing abnormal phenylalanine metabolism.
  • Symptoms: Mousy odor in urine, sweat, and breath.
  • Screening Tests: Guthrie bacterial inhibition test using B. subtilis and beta-2-thienylalanine.
  • Confirmatory Test: Ion exchange HPLC.

Notable Crystals in Urine Analysis

• Uric Acid Crystals: Pathologic conditions like Lesch-Nyhan syndrome lead to unique shapes (rhombic or diamond-shaped).
• Calcium Oxalate Crystals: Can present as monohydrate (oval/dumbbell shaped) or dihydrate (envelope-shaped).### Renal Glucosuria
• Normal blood glucose with increased urine glucose indicates defective tubular reabsorption of glucose.
• Primary finding is glucosuria, leading to increased glucose in urine.

Amniotic Fluid

• Present in the amnion, which surrounds the fetus; generated by the placenta.
• Functions include cushioning the fetus, stabilizing temperature, allowing movement, and facilitating lung development.
• Normal amniotic fluid volume in the third trimester: 800 - 1200 mL, primarily from fetal urine.
• Amniocentesis collects up to 30 mL for genetic defect assessment and fetal lung maturity evaluation.

Tests for Neural Tube Defects

• Spina Bifida: Incomplete closure of the backbone and spinal cord membranes.
• Anencephaly: Absence of major parts of brain and skull during embryonic development.
• Alpha-feto protein increases in neural tube defects and decreases in Down syndrome.

Fetal Lung Maturity Testing

• Lecithin/Sphingomyelin (L/S) ratio is the reference method, assessing surfactant for alveolar stability.
• Increased opacity at 450 nm in amniotic fluid is seen in hemolytic disease of the newborn (HDN).
• Test results are plotted on Liley graph to indicate fetal health zones.

Specimen Collection and Handling

• Sputum specimens are collected primarily from upper and lower respiratory tracts.
• Specimen for amniotic fluid is collected via amniocentesis, protected from light for certain tests.
• Main specimen for neurodiagnostic tests includes cerebrospinal fluid (CSF) collected via lumbar puncture.

Cerebrospinal Fluid (CSF) Analysis

• CSF functions: nutrient supply, waste removal, and mechanical protection for the brain.
• Normal WBC count for adults: 0-5 WBCs/uL; neonates: 0-30 WBCs/uL.
• Typical CSF appearance: crystal clear (normal); turbid indicates increased WBCs; xanthochromic suggests hemorrhage.

Seminal Fluid Analysis

• Seminal fluid is composed of spermatozoa, seminal fluid, prostatic fluid, and bulboourethral fluid.
• Sperm concentration of >20 million sperms/mL is normal.
• Specimen collection involves abstinence of 2-7 days, and entire ejaculate is collected for analysis.

Stool Analysis (Fecalysis)

• Normal feces consist of 75% water and 25% solids, with an odor due to indole and skatole.
• Macroscopic appearances vary: black for upper GI bleeding, red for lower GI bleeding, pale yellow for bile duct obstruction.
• Microscopic examination detects steatorrhea (fat) and creatorrhea (muscle fibers), and fecal leukocytes indicate invasive infections.

Sputum Indicators

• Sialic acid contributes to sputum viscosity, typically collected from tracheobronchial secretions.
• Presence of Charcot-Leyden crystals indicates bronchial asthma and acute respiratory conditions.

Miscellaneous

• Specimen color in various bodily fluids can indicate conditions such as trauma, infection, or the presence of old blood.
• Mucin Clot Test evaluates synovial fluid for joint conditions, indicating the presence of hyaluronic acid.

Test your knowledge on key biochemistry topics including the characteristic shapes of uric acid crystals and calcium oxalate dihydrate. Additionally, evaluate your understanding of phenylketonuria screening tests and waste classification. This quiz covers essential concepts relevant to biochemistry and metabolic disorders.